EP1536120A2 - Abgassteuerungsvorrichtung und -methode für eine Brennkraftmaschine - Google Patents

Abgassteuerungsvorrichtung und -methode für eine Brennkraftmaschine Download PDF

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Publication number
EP1536120A2
EP1536120A2 EP04028130A EP04028130A EP1536120A2 EP 1536120 A2 EP1536120 A2 EP 1536120A2 EP 04028130 A EP04028130 A EP 04028130A EP 04028130 A EP04028130 A EP 04028130A EP 1536120 A2 EP1536120 A2 EP 1536120A2
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EP
European Patent Office
Prior art keywords
amount
exhaust gas
particulate matter
internal combustion
combustion engine
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP04028130A
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English (en)
French (fr)
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EP1536120A3 (de
EP1536120B1 (de
Inventor
Tetsuji Tomita
Tatsumasa Sugiyama
Jun Tahara
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Toyota Motor Corp
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Toyota Motor Corp
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Publication of EP1536120A3 publication Critical patent/EP1536120A3/de
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0093—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
    • F02D35/0015—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for using exhaust gas sensors
    • F02D35/0023—Controlling air supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
    • F02B29/04—Cooling of air intake supply
    • F02B29/0406—Layout of the intake air cooling or coolant circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D2041/0017—Controlling intake air by simultaneous control of throttle and exhaust gas recirculation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/08—Exhaust gas treatment apparatus parameters
    • F02D2200/0802—Temperature of the exhaust gas treatment apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/08—Exhaust gas treatment apparatus parameters
    • F02D2200/0812—Particle filter loading
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/02—EGR systems specially adapted for supercharged engines
    • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
    • F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/35—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the invention relates to an exhaust gas control apparatus which purifies exhaust gas discharged from an internal combustion engine using an exhaust gas control catalyst, and a control method thereof.
  • An exhaust gas control apparatus for a diesel engine in which particulate matter (PM) contained in exhaust gas is captured using an exhaust gas control catalyst provided in an exhaust passage, and a catalyst recovery control for recovering the exhaust gas control catalyst by removing the accumulated particulate matter is performed.
  • the catalyst recovery control is performed, the amount of particulate matter accumulated in the exhaust gas control catalyst is estimated based on an operating state of an internal combustion engine.
  • a predetermined condition for recovery including a condition that the estimated amount of the accumulated particulate matter is equal to or larger than a predetermined value
  • fuel is supplied to a portion upstream of the exhaust gas control catalyst in the exhaust passage, from an exhaust gas fuel supply valve that is provided separately from a fuel injection valve for driving the engine.
  • the supplied fuel is burned in the exhaust gas control catalyst, and heat is generated.
  • the heat increases the temperature of the exhaust gas control catalyst (hereinafter, referred to as "catalyst temperature") to a temperature at which the particulate matter can be removed (approximately 600 °C). Accordingly, the particulate matter can be burned to be removed, and thus the exhaust gas control catalyst is recovered.
  • the exhaust gas control catalyst does not perform an exhaust gas control function when the catalyst temperature exceeds a certain value (i.e., an upper limit temperature). Therefore, it is necessary to prevent the catalyst temperature from exceeding the upper limit temperature. Accordingly, for example, when the engine is decelerated during the catalyst recovery control, an intake throttle valve in an intake passage is fully opened or substantially fully opened. In this technology, the amount of air contained in the exhaust gas is increased so as to increase the amount of heat that is removed by the air in the exhaust gas while the air in the exhaust gas passes through the exhaust gas control catalyst, whereby an increase in the catalyst temperature is suppressed.
  • JP-A-2002-371889 discloses a technology in which an air-fuel ratio of exhaust gas is made rich for a predetermined time period when an engine is decelerated and a NOx catalyst is active for recovering the NOx catalyst, and then fuel cut is performed.
  • the catalyst temperature may be sharply increased to exceed the upper limit temperature.
  • the amount of particulate matter accumulated in the exhaust gas control catalyst can be prevented from being increased by fuel cut.
  • the fuel injection is restarted after fuel cut, for example, when the vehicle starts to run at a constant speed after deceleration, the particulate matter may start to be accumulated again, and thus the amount of the accumulated particulate matter may be increased. Accordingly, even in the technology disclosed in the aforementioned Japanese Patent Laid-Open Publication No. 2002-371889, the aforementioned problem may occur when the engine is decelerated while the amount of the accumulated particulate matter is large during the catalyst recovery control.
  • a first aspect of the invention relates to an exhaust gas control apparatus for an internal combustion engine, which includes an exhaust gas control catalyst provided in an exhaust passage for the internal combustion engine, and in which the exhaust gas control catalyst is recovered by burning and removing particulate matter accumulated in the exhaust gas control catalyst.
  • the exhaust gas control catalyst includes control means for performing a control such that an amount of air taken in the internal combustion engine becomes small when an amount of the accumulated particulate matter is large while the internal combustion engine is decelerated, as compared to when the amount of the accumulated particulate matter is small while the internal combustion engine is decelerated.
  • the control means may perform a control such that the amount of air taken in the internal combustion engine becomes smaller as the amount of the accumulated particulate matter becomes larger.
  • a second aspect of the invention relates to an exhaust gas control apparatus for an internal combustion engine, which includes an exhaust gas control catalyst provided in an exhaust passage for the internal combustion engine, and in which the exhaust gas control catalyst is recovered by burning and removing particulate matter accumulated in the exhaust gas control catalyst.
  • the exhaust gas control apparatus includes control means for suppressing an increase in an amount of air taken in the internal combustion engine by a large amount when an amount of the accumulated particulate matter is large while the internal combustion engine is decelerated, as compared to when the amount of the accumulated particulate matter is small while the internal combustion engine is decelerated.
  • the particulate matter in the exhaust gas discharged from the internal combustion engine is captured by the exhaust gas control catalyst.
  • the particulate matter thus captured and accumulated in the exhaust gas control catalyst is burned and removed, whereby the exhaust gas control catalyst is recovered.
  • Air in the exhaust gas removes heat of the exhaust gas control catalyst while passing through the exhaust gas control catalyst, and thus suppress an increase in the catalyst temperature.
  • the amount of the exhaust gas is decreased, and accordingly the amount of air in the exhaust gas is decreased while the internal combustion engine is decelerated, the amount of heat removed by the air is decreased, as compared to when the engine is not decelerated.
  • the accumulated particulate matter reacts with oxygen in the air (i.e., the accumulated particulate matter is oxidized), and heat is generated.
  • the amount of generated heat is increased as the amount of particulate matter is increased, and as the amount of air (oxygen) is increased.
  • the degree of a change (an increase) in the temperature of the exhaust gas control catalyst is decided based on balance between the amount of heat removed by the air in the exhaust gas and the amount of generated heat due to oxidation of the particulate matter.
  • an increase in the amount of air taken in the internal combustion engine is suppressed by a large amount when the internal combustion engine is decelerated while the amount of accumulated particulate matter is large during recovery of the exhaust gas control catalyst, as compared to when the engine is decelerated while the amount of the accumulated particulate matter is small. Therefore, the amount of oxygen involved in the oxidation reaction is decreased, and accordingly the amount of heat generated due to the reaction is decreased. As a result, it is possible to suppress damage to the exhaust gas control function of the exhaust gas control catalyst due to an excessive increase in the catalyst temperature.
  • the control means may suppress the increase in the amount of air taken in the internal combustion engine by a larger amount as the amount of the accumulated particulate matter becomes larger.
  • the control means suppresses the increase in the amount of air taken in the internal combustion engine by a small amount, and the amount of air taken in the internal combustion engine is large. Therefore, the amount of the particulate matter involved in the oxidation reaction is small, but the amount of oxygen involved in the oxidation reaction is large. Meanwhile, when the amount of the accumulated particulate matter is large, the control means suppresses the increase in the amount of air taken in the internal combustion engine by a large amount, and the amount of air taken in the internal combustion engine is small. Therefore, the amount of the particulate matter involved in the oxidation reaction is large, but the amount of oxygen involved in the oxidation reaction is small. Accordingly, the amount of heat generated due to burning of the particulate matter can be made substantially constant irrespective of the amount of the accumulated particulate matter, and accordingly the catalyst temperature can be made substantially constant.
  • the internal combustion engine may include an intake throttle valve which adjusts an amount of air taken in a combustion chamber through an intake passage; and the control means may suppress the increase in the amount of air taken in the internal combustion engine by suppressing an opening operation of the intake throttle valve.
  • the opening operation of the intake throttle valve is suppressed, as compared when the engine is decelerated while the amount of the accumulated particulate matter is small. Since the opening operation of the intake throttle valve is suppressed, the increase in the amount of air taken in the combustion chamber through the intake passage is suppressed, which decreases the amount of oxygen involved in the oxidation reaction of the particulate matter accumulated in the exhaust gas control catalyst.
  • the internal combustion engine may include an exhaust gas recirculation device which recirculates part of exhaust gas to a combustion chamber through an intake passage; and the control means may suppress the increase in the amount of air taken in the internal combustion engine by increasing an amount of exhaust gas which is recirculated by the exhaust gas recirculation device.
  • the control means may make a determination on the amount of the accumulated particulate matter based on a gradient of an increase in a temperature of the exhaust gas control catalyst, and may suppress the increase in the amount of air taken in the internal combustion engine using a result of the determination.
  • the amount of heat generated due to the oxidation reaction tends to be larger, and the gradient (degree) of the increase in the catalyst temperature tends to be larger as the amount of the accumulated particulate matter becomes larger.
  • the amount of the accumulated particulate matter can be determined based on the gradient of the increase in the catalyst temperature.
  • the increase in the amount of air taken in the internal combustion engine is suppressed based on the result of the determination. Accordingly, it is possible to reliably suppress damage to the exhaust gas control function of the exhaust gas control catalyst due to an excessive increase in the catalyst temperature.
  • the amount of the accumulated particulate matter that is determined based on the gradient of the increase in the catalyst temperature may be corrected.
  • the control means may determine that the amount of the accumulated particulate matter is large, and may suppress the increase in the amount of air taken in the internal combustion engine when the gradient of the increase in the temperature of the exhaust gas control catalyst is equal to or larger than a reference value.
  • the catalyst temperature exceeds an upper limit temperature at which the exhaust gas control catalyst does not perform the exhaust gas control function. In this case, it is preferable to promote burning of the particulate matter in order to recover the exhaust gas control catalyst.
  • the increase in the amount of air taken in the internal combustion engine may be suppressed when the gradient of the increase in the temperature of the exhaust gas control catalyst is equal to or larger than the reference value as a result of comparison therebetween, and the increase in the amount of air taken in the internal combustion engine may not be suppressed when the gradient of the increase in the temperature of the exhaust gas control catalyst is smaller than the reference value.
  • the reference value may be set to the largest value in a region in which the catalyst temperature does not exceed the upper limit temperature even if the increase in the amount of air taken in the internal combustion engine is not suppressed, in an entire range of values of the gradient.
  • the control means may suppress the increase in the amount of air taken in the internal combustion engine by a larger amount as a difference between the gradient of the increase in the temperature of the exhaust gas control catalyst and a predetermined reference value becomes larger.
  • the reference value may be set to the largest value in a region in which the catalyst temperature does not exceed the upper limit temperature even if the increase in the amount of air taken in the internal combustion engine is not suppressed, in an entire range of values of the gradient.
  • the particulate matter can be oxidized (burned) using oxygen of the amount corresponding to the amount of the accumulated particulate matter, and an excessive increase in the catalyst temperature can be effectively suppressed by making the amount of heat substantially constant, irrespective of the amount of the accumulated particulate matter.
  • the difference between the gradient of the increase in the catalyst temperature and the reference value is equal to or lower than 0, that is, when the gradient is small, the increase in the amount of air taken in the internal combustion engine is not suppressed, whereby the exhaust gas control catalyst can be recovered while suppressing an excessive increase in the catalyst temperature.
  • the control means may estimate the amount of the accumulated particulate matter based on a gradient of the increase in the temperature of the exhaust gas control catalyst, and may suppress the increase in the amount of air taken in the internal combustion engine when the estimated amount of the accumulated particulate matter is equal to or larger than a predetermined amount.
  • the amount of the accumulated particulate matter can be estimated based on the gradient of the increase in the catalyst temperature.
  • the predetermined value may be set to a value corresponding to the largest value in a region in which the catalyst temperature does not exceed the upper limit temperature even if the increase in the amount of air taken in the internal combustion engine is not suppressed, in an entire range of values of the gradient.
  • the amount of oxygen involved in the oxidation reaction of the particulate matter can be decreased, and the increase in the amount of heat generated due to the oxidation reaction can be suppressed in spite of the large amount of the accumulated particulate matter.
  • the exhaust gas control catalyst can be recovered while suppressing an excessive increase in the catalyst temperature.
  • a third aspect of the invention relates to a method in which an exhaust gas control catalyst provided in an exhaust passage for an internal combustion engine is recovered by burning and removing particulate matter accumulated in the exhaust gas control catalyst.
  • the method includes the steps of determining whether an amount of the accumulated particulate matter is large; and performing a control such that an amount of air taken in the internal combustion engine becomes small when it is determined that the amount of the accumulated particulate matter is large while the internal combustion engine is decelerated, as compared to when it is determined that the amount of the accumulated particulate matter is small while the internal combustion engine is decelerated.
  • a fourth aspect of the invention relates to a method in which an exhaust gas control catalyst provided in an exhaust passage for an internal combustion engine is recovered by burning and removing particulate matter accumulated in the exhaust gas control catalyst.
  • the method includes the steps of determining whether an amount of the accumulated particulate matter is large; and suppressing an increase in an amount of air taken in the internal combustion engine by a large amount when it is determined that the amount of the accumulated particulate matter is large while the internal combustion engine is decelerated, as compared to when it is determined that the amount of the accumulated particulate matter is small while the internal combustion engine is decelerated.
  • FIG 1 shows a diesel engine (hereinafter, referred to simply as "engine") 10 installed in a vehicle, and an exhaust gas control apparatus 11 for the engine 10.
  • the engine 10 mainly includes an intake passage 12, a combustion chamber 13, and an exhaust passage 14.
  • An air cleaner 15 for purifying air taken in the intake passage 12 is provided in the most upstream side of the intake passage 12.
  • a compressor 16A of a turbocharger 16, an intercooler 17, and an intake throttle valve 18 are provided in this order in a direction from the air cleaner 15 to the downstream side of the intake passage 12.
  • An intake manifold 19 is provided downstream of an intake throttle valve 18 in the intake passage 12, as a branch portion of the intake passage 12.
  • the intake passage 12 is connected to the combustion chamber 13 of each cylinder of the engine 10 through this branch portion.
  • a fuel injection valve 21 for injecting fuel used for combustion in the combustion chamber 13 is provided for each combustion chamber 13.
  • Fuel is supplied to each fuel injection valve 21 from a fuel tank 23 through a fuel supply passage 22.
  • a fuel pump 24, and a common rail 25 are provided in the fuel supply passage 22.
  • the fuel pump 24 sucks the fuel from the fuel tank 23, and pressurizes and discharges the fuel.
  • the common rail 25 is a high pressure fuel pipe for storing the discharged high-pressure fuel.
  • the fuel injection valve 21 of each cylinder is connected to the common rail 25.
  • an exhaust manifold 26 for collecting exhaust gas discharged from the combustion chamber 13 of each cylinder, and a turbine 16B of a turbocharger 16 are provided in the exhaust passage 14.
  • an exhaust gas recirculation (hereinafter, referred to as "EGR") device 27 which recirculates part of the exhaust gas to the intake air is employed.
  • the EGR device 27 includes an EGR passage 28 which connects the intake passage 12 with the exhaust passage 14. An upstream side of the EGR passage 28 is connected to a portion between the exhaust manifold 26 and the turbine 16B in the exhaust passage 14.
  • an EGR cooler catalyst 29 for purifying the recirculated exhaust gas, an EGR cooler 31 for cooling the recirculated exhaust gas, and an EGR valve 32 for adjusting the flow amount of the recirculated exhaust gas are provided in this order from the upstream side.
  • a downstream side of the EGR passage 28 is connected to a portion between the intake throttle valve 18 and the intake manifold 19 in the intake passage 12.
  • the air taken in the intake passage 12 is purified by the air cleaner 15, and then is introduced to the compressor 16A of the turbocharger 16.
  • the compressor 16A compresses the introduced air, and discharges the compressed air to the intercooler 17.
  • the air whose temperature has been increased due to compression is cooled by the intercooler 17, and then is distributed to the combustion chamber 13 of each cylinder via the intake throttle valve 18 and the intake manifold 19.
  • flow amount of the air in the intake passage 12 is adjusted by controlling the opening degree of the intake throttle valve 18.
  • the fuel injection valve 21 injects the fuel into the combustion chamber 13 to which the air has been introduced during the compression stroke in each cylinder.
  • the mixture of the air introduced through the intake passage 12 and the fuel injected from the fuel injection valve 21 is burned in the combustion chamber 13.
  • the piston 20 is reciprocated by the high-temperature high-pressure combustion gas that is generated at this time, and thus the crankshaft (not shown) that is an output shaft of the engine 10 is rotated, whereby the driving power of the engine 10 is obtained.
  • the rotational speed of the crankshaft is changed by a transmission (not shown), and the changed rotational speed is transmitted to driving wheels.
  • the exhaust gas generated by combustion in the combustion chamber 13 of each cylinder is introduced to the turbine 16B of the turbocharger 16 through the exhaust manifold 26.
  • the turbine 16B is driven by force of the introduced exhaust gas, the compressor 16A provided in the intake passage 12 is driven in association with the turbine 16B, whereby the air is compressed.
  • part of the exhaust gas generated due to the combustion is introduced to the EGR passage 28.
  • the exhaust gas introduced to the EGR passage 28 is purified by the EGR cooler catalyst 29, is cooled by the EGR cooler 31, and then is recirculated to the air on the downstream side of the intake throttle valve 18 in the intake passage 12.
  • the amount of the exhaust gas thus recirculated is adjusted by controlling the opening degree of the EGR valve 32.
  • the engine 10 is configured as described above. Next, the exhaust gas control apparatus 11 for purifying the exhaust gas discharged from the engine 10 will be described.
  • the exhaust gas control apparatus 11 includes an exhaust gas fuel supply valve 33, and three catalyst converters that are exhaust gas control catalysts (a first catalyst converter 34, a second catalyst converter 35, and a third catalyst converter 36).
  • the first catalyst converter 34 is provided downstream of the turbine 16B.
  • the first catalyst converter 34 supports a storage reduction NOx catalyst.
  • the first catalyst converter 34 stores nitrogen oxides NOx in the exhaust gas.
  • the first catalyst converter 34 reduces and removes the stored nitrogen oxides NOx using supplied unbumed fuel components that serve as a reducing agent.
  • the second catalyst converter 35 is provided downstream of the first catalyst converter 34.
  • the second catalyst converter 35 is formed using porous material which permits gas components in the exhaust gas to pass therethrough, and inhibits the particulate matter in the exhaust gas from passing therethrough.
  • the second catalyst converter 35 supports the storage reduction NOx catalyst.
  • the third catalyst converter 36 is provided downstream of the second catalyst converter 35.
  • the third catalyst converter 36 supports an oxidation catalyst for purifying the exhaust gas by oxidizing the hydrocarbon HC and carbon monoxide CO in the exhaust gas.
  • the exhaust gas fuel supply valve 33 is provided in an exhaust gas collection portion of the exhaust manifold 26. Also, the exhaust gas fuel supply valve 33 is connected to the fuel pump 24 via a fuel passage 37. The exhaust gas fuel supply valve 33 injects and supplies the fuel supplied from the fuel pump 24 into the exhaust gas as the reducing agent. The exhaust gas is temporarily brought into the reduction atmosphere by the supplied fuel, whereby the nitrogen oxides NOx stored in the first catalyst converter 34 and the second catalyst converter 35 are reduced and removed. Further, the particulate matter is captured at the same time in the second catalyst converter 35.
  • An electronic control unit 41 controls the engine 10 and the exhaust gas control apparatus 11 that have been described.
  • the electronic control unit 41 includes a CPU for performing various processings related to the control of the engine 10, a ROM for storing programs and data required for the control, a RAM for storing the results of the processings performed by the CPU, and the like, a backup RAM for storing and maintaining various data even after electric supply is stopped, input/output ports for receiving and outputting information from and to the outside, and the like.
  • the input port of the electronic control unit 41 is connected to an air flow meter 42 for detecting the flow amount of air in the intake passage 12 (intake air amount), an NE sensor 43 for detecting an engine rotational speed (NE), a throttle sensor 44 for detecting the opening degree of the intake throttle valve 18 (throttle valve opening degree), and a coolant temperature sensor 45 for detecting the temperature of the coolant of the engine 10. Further, the input port is connected to an accelerator sensor 46 for detecting the depression amount of an accelerator pedal (accelerator operation amount), a vehicle speed sensor 47 for detecting a running speed of the vehicle (vehicle speed), and the like.
  • an output port of the electronic control unit 41 is connected to the intake throttle valve 18, the fuel injection valve 21, the fuel pump 24, the exhaust gas fuel supply valve 33, the EGR valve 32, and the like.
  • the electronic control unit 41 performs various operation controls for the engine 10 by controlling the devices connected to the output port, based on the results of detection performed by the sensors 42 to 47.
  • the various operation controls include a fuel injection control, a throttle valve control, an EGR control, a control related to purification of the exhaust gas, and the like.
  • a fuel injection control the amount of the fuel injected from the fuel injection valve 21 and the injection timing are decided.
  • a basic fuel injection amount (basic injection time period) is calculated according to the engine operating state such as the engine rotational speed and the accelerator operation amount, by referring to a map or the like. Then, the basic injection time period is corrected based on the coolant temperature, the intake air amount, and the like, whereby a final injection time period is decided.
  • basic fuel injection timing is calculated according to the engine operating state such as the engine rotational speed and the accelerator operation amount, by referring to a predetermined map or the like.
  • the basic injection timing is corrected based on the coolant temperature, the intake air amount, and the like, whereby final injection timing is decided.
  • the output signal of the NE sensor 43 matches an injection start time, electric current starts to be supplied to the fuel injection valve 21.
  • the injection time period has elapsed since the injection start time, supply of the electric current is stopped.
  • a target throttle valve opening degree is calculated according to the engine rotational speed and the accelerator operation amount.
  • the intake throttle valve 18 is controlled such that the actual throttle valve opening degree detected by the throttle sensor 44 becomes close to the target throttle valve opening degree.
  • the EGR control for example, it is determined whether a condition for performing the EGR control is satisfied based on the engine rotational speed, the coolant temperature, the accelerator operation amount, and the like.
  • the condition for performing the EGR control includes a condition that the coolant temperature is equal to or higher than a predetermined value, a condition that the engine 10 has continued to be operated for a predetermined time or more since the engine 10 is started, a condition that the amount of a change in the accelerator operation amount is a positive value, and the like. If the condition for performing the EGR control is not satisfied, the EGR valve 32 is maintained in a fully closed state. If the condition for performing the EGR control is satisfied, a target opening valve degree of the EGR valve 32 is calculated according to the engine rotational speed, the accelerator operation amount, and the like, by referring to a predetermined map or the like.
  • a feedback control for the EGR valve opening degree is performed using the intake air amount as a parameter.
  • a target intake air amount of the engine 10 is decided using the accelerator operation amount, the engine rotational speed, and the like as parameters.
  • the actual intake air amount detected by the air flow meter 42 is compared with the target intake air amount.
  • the EGR valve 32 is closed by a predetermined degree. In this case, the amount of the EGR gas flowing into the intake passage 12 from the EGR passage 28 is decreased, and accordingly, the amount of the EGR gas taken in the combustion chamber 13 is decreased. As a result, the amount of fresh air taken in the combustion chamber 13 is increased by an amount corresponding to the amount by which the EGR gas is decreased.
  • the EGR valve 32 is opened by a predetermined amount.
  • the amount of the EGR gas flowing into the intake passage 12 from the EGR passage 28 is increased, and accordingly, the amount of the EGR gas taken in the combustion chamber 13 is increased.
  • the amount of fresh air taken in the combustion chamber 13 is decreased by an amount corresponding to the amount by which the EGR gas is increased.
  • the intake throttle valve 18 is closed by a predetermined degree.
  • the degree of intake negative pressure (the difference between the atmospheric pressure and the intake pressure) becomes large on the downstream side of the intake throttle valve 18 in the intake passage 12. Therefore, the amount of the EGR gas taken in the intake passage 12 from the EGR passage 28 is increased.
  • the control related to purification of the exhaust gas includes a control for the exhaust gas control catalyst.
  • a control for the exhaust gas control catalyst In the control for the exhaust gas control catalyst, four catalyst control modes, that are, a catalyst recovery control mode, a sulfur poisoning recovery control mode, a NOx reduction control mode, and a normal control mode are set.
  • the electronic control unit 41 selects and performs the catalyst control mode according to the states of the catalyst converters 34 to 36.
  • the particulate matter accumulated particularly in the second catalyst converter 35 reacts with oxygen in air (i.e., the particulate matter is burned), the particulate matter is changed to carbon dioxide CO 2 and water H 2 O, and CO 2 and H 2 O are discharged, whereby the second catalyst converter 35 is recovered. Heat is generated due to the oxidation reaction. As the amount of the particulate matter becomes larger, and as the amount of air (oxygen) becomes larger, the amount of generated heat becomes larger.
  • the amount of the particulate matter accumulated in the second catalyst converter 35 is estimated based on the operating state of the engine 10. For example, the amount of generated particulate matter is obtained each time the fuel injection is performed, using a map in which a relationship between the fuel injection amount and the engine rotational speed, and the amount of generated particulate matter is predefined. The amount of the accumulated particulate matter is obtained by accumulating the amount of generated particulate matter which is obtained each time the fuel injection is performed.
  • the exhaust gas fuel supply valve 33 which is provided separately from the fuel injection valve 21 for driving the engine supplies the fuel to a portion upstream of the second catalyst converter 35 in the exhaust passage 14.
  • the condition for recovery includes a condition that the estimated amount of the accumulated particulate matter is equal to or larger than a predetermined value ⁇ .
  • the supplied fuel is burned in the second catalyst converter 35, and heat is generated.
  • the temperature of the second catalyst converter 35 (the catalyst temperature and the catalyst bed temperature) is increased to a temperature at which the particulate matter can be removed (approximately 600 °C) due to the generated heat. As a result, the particulate matter is burned and removed, and the second catalyst converter 35 is recovered.
  • the second catalyst converter 35 can perform the exhaust gas control function in a certain temperature range, and cannot purify the exhaust gas at atmospheric temperature higher than the upper limit value of the temperature range (hereinafter, referred to as "upper limit temperature", approximately 800 °C). Therefore, the catalyst recovery control needs to be performed such that the catalyst temperature of the second catalyst converter 35 does not exceed the upper limit temperature.
  • upper limit temperature approximately 800 °C
  • the air contained in the exhaust gas removes the heat of the second catalyst converter 35 while passing through the second catalyst converter 35, thereby suppressing an increase in the catalyst temperature. Accordingly, by appropriately using the air which removes the heat, the amount of heat generated in the second catalyst converter 35 and the amount of heat removed from the second catalyst converter 35 can be balanced. As a result, the aforementioned requirement can be satisfied, that is, the catalyst temperature can be prevented from exceeding the upper limit temperature.
  • the amount of the exhaust gas is decreased, and accordingly the amount of the air in the exhaust gas is decreased. Therefore, the amount of heat removed by the air is small as compared to when the vehicle is not decelerated.
  • the sulfur poisoning recovery control mode sulfur components are discharged so that the NOx storage reduction catalysts in the first catalyst converter 34 and the second catalyst converter 35 recover from sulfur poisoning when the NOx storage reduction catalysts in the first catalyst converter 34 and the second catalyst converter 35 are poisoned with sulfur and the NOx storage capacity is decreased.
  • the catalyst temperature is increased to a high temperature (for example, 600 to 700 °C) by repeatedly supplying the fuel from the exhaust gas fuel supply valve 33.
  • the nitrogen oxides NOx stored in the first catalyst converter 34 and the second catalyst converter 35 is reduced to nitrogen N 2 , carbon dioxide CO 2 , and water H 2 O, and then the nitrogen N 2 , the carbon dioxide CO 2 , and the water H 2 O are discharged.
  • the catalyst temperature is made relatively low (for example, 250 to 500 °C) by intermittently supplying the fuel from the exhaust gas fuel supply valve 33 at relatively long time intervals.
  • the catalyst control mode other than the catalyst recovery control mode, the sulfur poisoning recovery control mode, and the NOx reduction control mode is the normal control mode. In the normal control mode, the reducing agent is not supplied from the exhaust gas fuel supply valve 33.
  • the intake throttle valve 18 may be fully opened, or substantially fully opened as a measure for preventing the catalyst temperature of the second catalyst converter 35 from exceeding the upper limit temperature. In this case, the amount of air contained in the exhaust gas is increased, and the amount of heat removed by the air in the exhaust gas while the air in the exhaust gas passes through the second catalyst converter 35 is increased, whereby the increase in the catalyst temperature is suppressed.
  • this measure may be ineffective when the amount of the accumulated particulate matter is large. That is, when the actual amount of the accumulated particulate matter is larger than the estimated value during the catalyst recovery control, a catalyst recovery time period in the catalyst recovery control is shorter than the time period required for recovering the second catalyst converter 35. Accordingly, the particulate matter is not burned and removed completely, and part of the particulate matter remains accumulated.
  • the intake throttle valve 18 is fully opened or substantially fully opened while the amount of the accumulated particulate matter is large, the amount of the exhaust gas is decreased due to deceleration, and the amount of heat removed by the air in the exhaust gas is decreased.
  • the catalyst temperature may exceed the upper limit temperature.
  • air amount control routine air amount control routine
  • step 100 the electronic control unit 41 determines whether the catalyst recovery control is being performed. For example, it is determined whether the catalyst recovery control mode is selected and is being performed. When a negative determination is made in step 100 (i.e., it is determined that the catalyst recovery control is not being performed), the air amount control routine is terminated. When an affirmative determination is made in step 100 (i.e., it is determined that the catalyst recovery control is being performed), it is determined whether deceleration of the engine 10 and the vehicle has been started in step 110. For example, it is determined that the vehicle speed detected by the vehicle speed sensor 47 is lower than that in a previous control cycle. When a negative determination is made in step 110, the air amount control routine is terminated. When an affirmative determination is made in step 110, it is determined whether the deceleration which is being performed is the first deceleration after the catalyst control mode is changed to the catalyst recovery control mode from the other mode in step 120.
  • the amount of the accumulated particulate matter is read for the catalyst recovery control in step 130.
  • the amount of the accumulated particulate matter has been calculated for the catalyst recovery control by a separate routine, based on the engine operating state (for example, the fuel injection amount and the engine rotational speed), as described above.
  • the target throttle valve opening degree of the intake throttle valve 18 is calculated according to the amount of the accumulated particulate matter.
  • a reference is made to a map in FIG. 3 in which the relationship between the amount of the accumulated particulate matter and the target throttle valve opening degree is predefined. In this map, tendency is different between a region where the amount of the accumulated particulate matter is equal to or smaller than a value D1 and a region where the amount of the accumulated particulate matter is larger than the value D1.
  • the target throttle valve opening degree is the maximum or substantially the maximum value when the amount of the accumulated particulate matter is small, and is decreased as the amount of the accumulated particulate matter is increased.
  • the relationship between the amount of the accumulated particulate matter and the target throttle valve opening degree is thus predefined so that the amount of heat generated due to the oxidation reaction of the particulate matter can be made substantially constant, and accordingly the catalyst temperature can be made substantially constant irrespective of the amount of the accumulated particulate matter, by changing the amount of air according to the amount of the accumulated particulate matter, since the amount of generated heat is decided by the amount of the particulate matter (the amount of the accumulated particulate matter) and the amount of air (oxygen) involved in the oxidation. That is, when the amount of the accumulated particulate matter is large, the amount of air is decreased so as to suppress heat generation. Meanwhile, when the amount of the accumulated particulate matter is small, the amount of air is increased so as to promote heat generation.
  • the target throttle valve opening degree is set to a value corresponding to full closing, irrespective of the amount of the accumulated particulate matter.
  • the intake throttle valve 18 is always fully closed.
  • the target throttle valve opening degree is set to a large value, as shown by a point X in FIG. 3. Then, after the process in step 140 is performed, the air amount control routine is terminated.
  • step 150 the estimated amount of the accumulated particulate matter is obtained based on the gradient of the increase in the catalyst temperature at the time of the first deceleration, using a map in FIG. 4A. Also, a correction amount for the amount of the accumulated particulate matter (the amount of the accumulated particulate matter that is obtained based on the engine operating state at the second deceleration and the subsequent deceleration) is obtained using a map in FIG. 4B.
  • the correction amount is obtained based on the difference between the amount of the accumulated particulate matter that is obtained based on the gradient of the increase in the catalyst temperature and the amount of the accumulated particulate matter that is obtained based on the engine operating state at the time of the first deceleration.
  • the gradient of the increase in the catalyst temperature is the amount of the increase in the catalyst temperature per unit time (refer to FIG. 5). For example, the gradient of the increase in the catalyst temperature that is calculated by a separate routine may be used.
  • the catalyst temperature can be estimated based on the engine operating state. Since the catalyst temperature becomes higher as the engine rotational speed becomes higher, and as the engine load becomes higher, the estimated value of the catalyst temperature (estimated catalyst temperature) can be calculated based on the engine rotational speed, the engine load, and the like. For example, the estimated catalyst temperature is calculated based on the present engine rotational speed and the present engine load according to a map in which the relationship between the engine rotational speed and the engine load, and the estimated catalyst temperature is defined, and the estimated catalyst temperature is used as the catalyst temperature.
  • the amount of the accumulated particulate matter becomes larger, the amount of heat generated due to the oxidation reaction tends to be larger, and the gradient (degree) of the increase in the catalyst temperature tends to be larger irrespective of the degree of deceleration, while the exhaust gas control catalyst is recovered. Therefore, by predefining the relationship between the gradient of the increase in the catalyst temperature and the amount of the accumulated particulate matter, the amount of the accumulated particulate matter can be estimated based on the gradient of the increase in the catalyst temperature.
  • the amount of the accumulated particulate matter is estimated according to the gradient of the increase in the catalyst temperature, using the map in FIG. 4A in which the relationship between the gradient of the increase in the catalyst temperature and the amount of the accumulated particulate matter is defined (refer to a point X in FIG. 4A).
  • the map in FIG. 4A in which the relationship between the gradient of the increase in the catalyst temperature and the amount of the accumulated particulate matter is defined (refer to a point X in FIG. 4A).
  • the gradient of the increase in the catalyst temperature is small, the amount of the accumulated particulate matter is small.
  • the amount of the accumulated particulate matter becomes larger.
  • step S160 the correction amount obtained in step 150 is reflected in the catalyst recovery control. That is, the amount of the accumulated particulate matter, which is calculated for the catalyst recovery control based on the engine operating state by the separate routine, is corrected using the correction amount obtained in step 150.
  • This correction makes it possible to perform the catalyst recovery control based on the more accurate amount of the accumulated particulate matter during a catalyst recovery time period required for burning and removing the particulate matter.
  • step 170 the target throttle valve opening degree of the intake throttle valve 18 is calculated based on the amount of the accumulated particulate matter thus corrected, referring to the map in FIG. 3 which is used in the aforementioned step 140 (refer to a point Y in FIG. 3).
  • the target throttle valve opening degree is set to a smaller value in the map in FIG. 3. Therefore, as the gradient of the increase in the catalyst temperature becomes larger, the target throttle valve opening degree is set to a smaller value.
  • the air amount control routine is terminated.
  • the target throttle valve opening degree calculated in steps 140, 170 is used as the target throttle valve opening degree in the aforementioned throttle valve control.
  • the intake throttle valve 18 is controlled such that the actual throttle valve opening degree detected by the throttle sensor 44 becomes close to the target throttle valve opening degree.
  • the processes in step 130 to step 170 in the aforementioned air amount control routine performed by the electronic control unit 41 can be regarded as the control means.
  • the air amount control routine for example, the vehicle speed, the target throttle valve opening degree, and the catalyst temperature vary as shown in FIG. 5.
  • the processes in step 100 to step 140 are performed in this order. Since the gradient of the increase in the catalyst temperature has not been obtained at this point, the target throttle valve opening degree is calculated according to the amount of the accumulated particulate matter obtained based on the engine operating state, using the map in FIG. 3.
  • the target throttle valve opening degree which is larger than the throttle valve opening degree before time t1 is obtained.
  • the intake throttle valve 18 is controlled such that the actual throttle valve opening degree becomes close to the target throttle valve opening degree. Since the intake throttle valve 18 is opened, the intake air amount is changed (increased). Accordingly, the amount of heat generated due to the oxidation reaction of the particulate matter is changed, and the catalyst temperature is changed. Since the gradient of the increase in the catalyst temperature at the time of the first deceleration has been obtained at the time of the second deceleration (at time t11) and the subsequent deceleration, the amount of the accumulated particulate matter that is corrected based on the gradient of the increase in the catalyst temperature is obtained using the maps in FIGS.
  • the target throttle valve opening degree is obtained based on the corrected amount of the accumulated particulate matter using the map in FIG. 3 (step 170).
  • the target throttle valve opening degree is calculated using the amount of the accumulated particulate matter which is more accurate than that calculated based on the engine operating state (the fuel injection amount and the engine rotational speed) without considering the gradient of the increase in the catalyst temperature. Since the intake throttle valve 18 is controlled such that the throttle valve opening degree becomes close to the target throttle valve opening degree, an excessive increase in the catalyst temperature can be suppressed.
  • the increase in the intake air amount may be suppressed by opening the EGR valve 32 so as to increase the amount of the recirculated exhaust gas (EGR amount), instead of suppressing the opening operation of the intake throttle valve 18.
  • the EGR amount when the EGR amount is increased, the amount of air taken in the combustion chamber 13 is decreased by the amount corresponding to the amount by which the EGR amount is increased. Thus, the amount of oxygen involved in the oxidation reaction of the particulate matter accumulated in the second catalyst converter 35 is decreased. Accordingly, in this case as well, it is possible to prevent the situation where the catalyst temperature is excessively increased to exceed the upper limit temperature, and the exhaust gas control function of the exhaust gas control catalyst is damaged, as in the aforementioned embodiment.
  • the structure of the map in FIG. 4A may be appropriately changed as long as the amount of the accumulated particulate matter is large when the gradient of the increase in the catalyst temperature is large, as compared to when the gradient of the increase in the catalyst temperature is small.
  • a range of the values of the gradient may be divided into two or more regions, and the amount of the accumulated particulate matter may be set for each region (in this case, the amount of the accumulated particulate matter is the same in one region).
  • the structure of the map in FIG. 3 may be appropriately changed as long as the target throttle valve opening degree is set to a small value when the amount of the accumulated particulate matter is large, as compared to when the amount of the accumulated particulate matter is small.
  • the range of the values of the amount of the accumulated particulate matter may be divided into two or more regions, and the target throttle valve opening degree may be set for each region (in this case, the target throttle valve opening degree is the same in one region).
  • the target throttle valve opening degree may be directly calculated based on the gradient of the increase in the catalyst temperature, without obtaining the amount of the accumulated particulate matter.
  • the gradient of the increase in the catalyst temperature may be calculated two or more times during the deceleration, and the amount of the accumulated particulate matter and the target throttle valve opening degree may be calculated based on the calculated gradients of the increase in the catalyst temperature.
  • the intake air amount may be maintained at a value before deceleration, instead of decreasing the amount by which the intake air amount is increased. Also, the intake air amount may be decreased, instead of suppressing the increase in the intake air amount.
  • the air amount control routine in FIG. 2 it may be determined which is larger between the amount of the accumulated particulate matter obtained based on the engine operating state and the amount of the accumulated particulate matter estimated based on the gradient of the increase in the catalyst temperature, and the target throttle valve opening degree may be calculated based on the amount of the accumulated particulate matter which is larger.
  • the target throttle valve opening degree is calculated according to the amount of the accumulated particulate matter estimated based on the gradient of the increase in the catalyst temperature.
  • the increase in the intake air amount may be suppressed, and when the gradient of the increase in the catalyst temperature is smaller than the reference value, the increase in the intake air amount may not be suppressed.
  • the increase in the intake air amount may be suppressed, and when the amount of the accumulated particulate matter is smaller than the predetermined value, the increase in the intake air amount may not be suppressed.
  • the reference value (or the predetermined value) may be set to the largest value in a region in which the catalyst temperature does not exceed the upper limit temperature even if the increase in the amount of air taken in the internal combustion engine is not suppressed, in an entire range of values of the gradient (or the estimated amount of the accumulated particulate matter).
  • the increase in the intake air amount is suppressed by a larger amount such that the intake air amount becomes smaller.
  • the particulate matter can be oxidized (burned) by oxygen of the amount corresponding to the amount of the accumulated particulate matter, and the amount of generated heat can be made substantially constant irrespective of the amount of the accumulated particulate matter. Accordingly, an excessive increase in the catalyst temperature can be effectively suppressed.
EP04028130A 2003-11-26 2004-11-26 Abgassteuerungsvorrichtung und -methode für eine Brennkraftmaschine Expired - Fee Related EP1536120B1 (de)

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EP2078839A1 (de) * 2008-01-11 2009-07-15 Peugeot Citroën Automobiles S.A. Strategie der Schnellerhitzung, um die Deaktivierung eines Oxidationskatalysators eines Dieselmotors zu kompensieren
WO2015118856A1 (en) * 2014-02-10 2015-08-13 Toyota Jidosha Kabushiki Kaisha Control device for internal combustion engine
WO2015181602A1 (en) * 2014-05-28 2015-12-03 Toyota Jidosha Kabushiki Kaisha Exhaust gas control apparatus of internal combustion engine
US10436129B2 (en) 2015-12-08 2019-10-08 Toyota Jidosha Kabushiki Kaisha Control device for internal combustion engine
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JP5163553B2 (ja) * 2009-03-11 2013-03-13 トヨタ自動車株式会社 ディーゼル機関の制御装置
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JP7281101B2 (ja) * 2019-04-23 2023-05-25 マツダ株式会社 エンジンの制御方法および制御装置

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EP2078839A1 (de) * 2008-01-11 2009-07-15 Peugeot Citroën Automobiles S.A. Strategie der Schnellerhitzung, um die Deaktivierung eines Oxidationskatalysators eines Dieselmotors zu kompensieren
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WO2015118856A1 (en) * 2014-02-10 2015-08-13 Toyota Jidosha Kabushiki Kaisha Control device for internal combustion engine
WO2015181602A1 (en) * 2014-05-28 2015-12-03 Toyota Jidosha Kabushiki Kaisha Exhaust gas control apparatus of internal combustion engine
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US9988960B2 (en) 2014-05-28 2018-06-05 Toyota Jidosha Kabushiki Kaisha Exhaust gas control apparatus of internal combustion
CN106414966B (zh) * 2014-05-28 2019-04-12 丰田自动车株式会社 内燃机的排气控制装置
US10436129B2 (en) 2015-12-08 2019-10-08 Toyota Jidosha Kabushiki Kaisha Control device for internal combustion engine
GB2614021A (en) * 2021-05-28 2023-06-28 Jaguar Land Rover Ltd Controller and method for controlling operation of a direct injection internal combustion engine
GB2614021B (en) * 2021-05-28 2024-03-06 Jaguar Land Rover Ltd Controller and method for controlling operation of a direct injection internal combustion engine

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DE602004011589T2 (de) 2009-01-29
DE602004011589D1 (de) 2008-03-20
EP1536120B1 (de) 2008-01-30
JP2005155500A (ja) 2005-06-16
ES2297326T3 (es) 2008-05-01

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